Search for a Higgs boson decaying into γ∗γ → eeγ in pp collisions at ￼√s = 8 TeV with the CMS detector

Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/69259

Title:	Search for a Higgs boson decaying into γ∗γ → eeγ in pp collisions at √s = 8 TeV with the CMS detector
Authors:	張秋萍;Chang,Chiu-Ping
Contributors:	物理學系
Keywords:	高能物理;希格斯粒子;粒子物理;大強子對撞機;Higgs boson;Particle Physics;LHC;CMS;High energy physics
Date:	2015-11-19
Issue Date:	2016-01-05 17:47:13 (UTC+8)
Publisher:	國立中央大學
Abstract:	本篇論文研究希格斯玻色子衰變成一個虛擬光子和一個光子，其中虛擬光子衰變成正負電子對，本分析使用質子-質子對撞，能量在8TeV的對撞於LHC的CMS偵測器記錄到總和亮度為19.7/fb的數據。終態為兩個非常靠近的正負電子以及一個高能量的光子，正負電子因為太靠近彼此而無法在電磁量能器內分辨為二。本實驗的結果與另一個實驗結果相互結合：希格斯玻色子衰變成一個虛擬光子和一個光子，其中虛擬光子衰變成渺子對，結果顯示在 120 GeV 到 150 GeV 重建的希格斯玻色子的質量區間並沒有過量的訊號。觀察（預測）的訊號強度上限在質量為 125 GeV 時為 6.7 (5.9+2.8-1.8) 倍的標準模型預測。;A search is described for a Higgs boson decaying into two photons, one of which has an internal conversion to an electron pair (eeγ). The analysis is performed using proton-proton collision data recorded with the CMS detector at the LHC at a centre-of-mass energy of 8 TeV, corresponding to an integrated luminosity of 19.7/fb. The events selected have a merged electron caused by two close-by electrons from low mass γ* decay and a high transverse momentum photon. The results are combined with H ->γγ -> μμγ final state, where dimuon mass below 20 GeV. No excess above background has been found in the three-body invariant mass range 120 < m(llγ) < 150 GeV. The observed (expected) limit for Higgs mass = 125 GeV is about 7.62(9.97+4.81-3.10) times the SM prediction for H ->γγ -> eeγ, 10.79(7.59+3.78-2.36) times the SM prediction for H ->γ*γ -> μμγ and 6.7(5.9+2.8-1.8) times the SM prediction for combined channel.
Appears in Collections:	[Graduate Institute of Physics] Electronic Thesis & Dissertation

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